Stackable projectiles typically comprise a warhead coupled to a propulsion unit. The propulsion unit usually takes the form of a tailpiece containing a propellant burner, a primer and other components, and which is shaped to accommodate the nose of a similar projectile. Such projectiles can be stacked nose to tail in the barrel of a weapon and fired sequentially using a suitable firing mechanism.
A propulsion unit can be crimped or screw threaded amongst other methods onto a warhead in order to couple the two together. Both crimping and screw threading are direct approaches of joining the warhead to the propulsion unit. However, crimping and screw-threading are not suitable if the propulsion unit is made of different materials. For example, if the warhead is made of metal and the propulsion unit is made of plastic.
Furthermore, different manufacturing parties produce different profiles of warheads and propulsion units, so crimping and screw threading may not be the appropriate methods for joining different profiles of warheads and propulsion units. In order to couple the different profiles of warheads to propulsion units, the profile of the propulsion unit is usually redesigned to accommodate the profile of the warhead. Alternatively, the profile of the warhead can be redesigned to accommodate the profile of the propulsion unit. However, redesigning the profile of the warhead or propulsion unit can be time consuming and costly.